Improvement in the construction of ordnance



N. WIARD.

Construction of Ordnance. i

No. 42,315. Patented Apr. 12, 1864 WWW Q jZiVGZZiOZ' 6M fwd hi1.

, I PHER. AsmNGTON. D C.

iirvrrn "rates ATENT @rrrea NORMAN WIARD, or NEW YORK, N. Y.

IMPROVEMENT IN THE CONSTRUCTION OF ORDNANCE.

Specification forming part of Letters Patent N0. @233 B5, dated April 12, 1864.

To a whom it ntay concern.-

Be it known that I, NORMAN WIARD, of the city, county, and State of New York, have invented a new and useful Improvement in 'Ordnance; and I do hereby declare that the following is a full and exact description of the same, which is prepared with a view to the issue of Letters Patent of the United States therefor.

Before commencing to describe this improvement it may be proper to presentbriefly some of the considerations showing the necessity therefor.

Great changes have been introduced into naval architecture, and proposed in fortifications, by the introduction of iron-clad ships and revolving forts. These changes involve the necessity for guns of greater caliber or longer range than have been heretofore employed, and so constructed as to be reasonably safe from bursting when used in confined turrets and casemates or on decks of ships. WVhen gunpowder is fired from a gun two prominent phenomena are to be observed-the wonderful expansive force which ejects the shot, and the heat which results from the combustion of the powder. The effect of the first has mainly been considered hitherto by ordnance officers,

while in reality in large guns the effect of the second, though of much more consequence,

has been disregarded; and to account'for the bursting of guns fabulous amounts of pressure have been attributed to gunpowder. Vast amounts of time and money have been expended with a view to the production of guns of the largest possible caliber, rifled and smooth bore, yet very large guns have never yet been introduced with success into actual service. Increasing the thickness or using material of greater tensile strengthas steel in place of cast-iron-does not add to theendurance of guns in the same proportion. After numerous trials it is still impossible to make a satisfactory safe gun, forged or cast, of any single material, to project shot or shell from either rifle or smooth bores above a very moderate weightpractically less, I may say,

than a hundred poundsto be used with fullservice charges of quick-burning powder, and fired rapidly, as the exigencies of service will sometimes require, when the state of the atmosphere is such as to keep the outside of the gun ata low temperature-as in rain, when the gun is exposed, or in cold weather.

My invention recognizes what has usually been overlooked, to wit: the heat imparted by the burning powder to the interior of the gun. If we fire a shot from a rifled cannon at an elevation that would give a range of one thousand three hundred {yards when the gun is hot, it projects the first shot, the gun being cold, only about one thousand yards; the sec- ,ond shot about one thousand two hundred force of gunpowder appears fromthis and many other examples to be due very largely,

if not principally, to heat, resembling steam in this respect. It has been proposed to keep guns cool by applying water; but aside from the unequal strain thus induced, it would be just as improper to prepare any devices to take the heat from the gun as it would be to work the cylinder of a steam-engine in a bath of cold water. The heat being withdrawn the tension of the gases is in both cases reduced. It is desirable, therefore, in order to obtain the greatest projectile force from the powder, to abstract as little heat as possible therefrom.

I accomplish this by allowing the inner surface of the piece to acquire and hold a high degree of heat; but this requires special provisions to avoid the destruction of the gun) If we wish a glass vessel at 60 to withstand a certain pressureasof a column of fluid at60 it will be necessary to make the wall sufficiently thick, estimated according to its tensile strength. It will then withstand the pressure on its interior surface, even if communi cated sud denly; but if after having prepared it to withstand the pressure, we wish to communicate the pressure accompanied by heat as of a column of melted metalto give equal pressure, (the vessel being at 60 at the beginning of the experiment,) its tensile strength would be suflicient to withstand the pressure; but the heat communicated to the inner metal of the wall would expand it within the outer metal, which would not be expanded at the same time, and the vessel would be broken by the unequal communication of the heat. Heat has a similar effect upon large guns as ordinarily constructed. In small guns this effect of heat is not so detrimental, as the whole thickness of the metal of the gun is within the range of the heat, or so nearly so that the elasticity and compressibility of the metal provides a compensation for the unequal expansion.

There being two forces acting upon guns which burstthe one the direct pressure of the gases evolved from the powder, and-the other the result of the expansion of the inner metal of the gun, both forces acting in the same directionit would seem difficult to show one to be pre-eminently the cause of the fracture. I provide for both.

The fractures of large guns of United States models'that hav'e burst are curiously alike in their direction. They usually extend through the center ofthe breech and re-en forceto a-point forward of the trunnions, and branch off at either side, generally breaking the gun into three great pieces. This direction of fracture holds whether the gun has the outlinesof the army colunibiad, ofthe Dahlgren gun, or of the Parrotgun, with its strong wrought-iron re-enforce, and Whether the gun be made of steel or of cast-iron. It would scarcely be expected when Dahlgrcn guns burst that the fracture would occur through the part where the metal has more than twice the thickness exhibited in the army colu1nbiadviz., from the bottom of the bore to the rear of the breech through the easeabelbut this principal direction is usually the result. If we prepare three plates ofmetalsay four inches thick, twelve inches wide, and sixty inches long-with planed surfaces, one, on being heated to an intense red heat, or about 1,600 Fahrenheit, will be found expanded onesixtieth part of its length, or will be sixty-one inches long. On placing it between the other two a part of its heat is at first communicated to their contiguous surfaces only. The expansion of the inner surface of each outside plate, while the outer surface remains cold, warps the latter to the form of segments of a circle. This expansion will account for the breaking of the gun through the cascabel beyond the range of the pressure made by the powder, if the outside plates are considered as representing the re-enforce of the gun. Guns mounted in turrets in the ordinary manner are liable to the serious objection that a part of the port is always open, and projectiles or parts of pro- I muzzles of the guns, in which case, from their liability to bound and rebound in the limited space inside the turret, they would be fearfully destructive. This error is corrected in the adaptation of a spherical gun to the turret, hereinafter described.

My present invention is designed to afford extraordinary strength in the construction of guns, when hot as well as when cold, by reason of the peculiar arrangement of materials, the great thickness and the compensation for the tendency to great expansion of the interior by the heat received there, as also for the elasticity of the metal when violently acted on mechanically by the force of the gases on its inner surfaces. It is also designed to afford great advantages by reason of its peculiar form and its construction in'certain details.

To enable others skilled in the art to make and use my invention, I will proceed to de scribe its construction and operation by the aid of the drawing and of the letters of reference denoted thereon.

The drawings represent a very large rifled gun with acaliber of fourteen inches. It is intended to weigh fifty-one tons, and to project a shot weighing one thousand pounds. It is composed of three metals steel, bronze, and lead. grees of heat in about the following proportions: Steel expands, l1; bronze, 19; lead, 28. Their relative conductin g powers are, lead, 180 steel, 360; bronze, 1,150. The gun, thus composed of three metals,-according to my invention, is exhibited in section in Figure 1. The right-hand side of Fig. 21s a half ofa front elevation, and the left-hand side of the same figure is half of a rear elevation, both with part of the outer shell removed to exhibit the interior. The casting A is a hollow sphere seven feet in diameter, cast .upon a core, leaving six inches thickness of metal. A cylindrical center, A, on one axis has also six inches thickness of metal, and stays A, four inches in diameter, radiate from the center of the external form, connecting the cylindrical center A with the outer shell, A These stays A, I term conductors of heat. The outer shell, A and the hollow cylinder A,that envelopes the steel lining, being of uniform thickness and cooled from all s urfaces, will be a' casting without strain, having been uniformly cooled. core that forms the chamber between A and A is supported in its proper place by distancecores through the outer shell, A resting upon the outer case of the mold. Through these distance-cores E are vents, by which the gases and heat from the chamber-core escapes as the metal flows into the mold in casting.

The first operation after removing the gun from the mold is to remove the sand of which the chamber-core is composed through the holes left by the distance cores, and then to clear out the chamber with acid in order to re move any sand that may adhere to its surface. After cleaning the metal casting thoroughly the whole external surface of A is hammered for the purpose of compressing the metal to its greatest density, and it is designed to affect the density of the metal to abouthalf its thickness. The interior of A, to be afterward lined with steel, is enlarged by pressure obtained by small rollers revolved by a sleeve, with ashaft for its center. The rollers are pressed outward against the surface as they revolve by wedges until the whole surface has been passed over many times, thus enlarging the diameter by a pressure on small surfaces until the density of the metal is also affected in this part to half its thickness. The holes left by the distancecores are then, with the exception of one, stopped by screw-plugs E E, &c., after which the chamber is filled with melted lead 0. After the gun has cooled a hydraulic or other press is attached to each of the holes in succession, and additional lead in this manner is These metals expand with equal de The d2.31l5 a forced in to give the sameamonnt of compressionto the inner surface of the chamber as had been given before to the outer surfacebyhammering. By this means most of the compressibility of the bronze is taken up.

The bore of the bronze A, to receive the steel lining B, is tapered, being about one inch smaller at the breech than at the muzzle. The steel lining is turned a very little larger than the bore, and with a corresponding taper, and is also forced into its place by a hydraulic press. The bronze metal about this steel lining has a strain of compression upon it from the pressure of the lead, and a strain of compression also rests upon the steel lining. Any pressure having a tendency to enlarge the diameter would be resisted directly by the strength of the outer shell, as when the gun is completed it is intended that nearly all the compressibility of the bronze shall have been destroyed by the hammering and by the press me of the lead, as well as a great part of its elasticity, by forcing the steel lining with great force into the tapered bore. The steel lining is to have only a sufficient thickness to retard a part of the heat from the combustion of the powder, so that the proper proportion of heat is communicated to the bronze, and this pro portion is regulated by the thickness of the steel lining. A space is left in the bore of the cylinder A; and after the insertion of the steel lining B this space is also filled with lead D. By this means careful fitting of the steel B to the bottom of the chamber in A is obviated, and after the lining B is forced-in against the shoulder at the muzzle end a proper amount of pressure can be equally distributed about the spherical end of the steel lining; and during the service of the gun this pressure can be corrected by the use of the screw d. The steel lining B is prevented from changing its position by any shock to the gun by a key, B, inserted in such direction as to prevent with drawal of the lining without first withdrawing the keys. This also prevents the lining from revolving in the gun by the pressure of the shot against the side of the lands. Bronze is one of the best among the conductors of heat. The l'leat-eonductors A radiate from the cen ter of the sphere, the bottom of tlie bore being continued beyond the center of the sphere, so that the mean center of heating-surface may be at the center of the gun. The lead is a conductor of pressure, it being more nearly incompressible than any other of the metals, which renders it eminently fit for this pur pose.

The enlargement .of the bore of this gun by pressure of the powderwonld require, therefore, the overcoming of the inertia of the weight of a frustum of a cone without compressibility from each square inch of surface against which the pressure of the powder is exerted. The projgctile being a cylinder, elastic and compressible, its inertia would be easier overcome than any, cone of the metal of the gun, having equal area at the surface of the bore, against which the pressure of the powder is exerted, and the inertia of the cone would have to be overcome instantly, while the inertia of the shot would be overcome gradually, or in successive disks of its length. i It is graduated at G, Fig. 2, for adjustment to the proper elevation. The addition of the tensile strength of the metal of the gun makes it unquestionable, therefore, that this gun cannot be burst by the pressure of the powder if the shot is free to move forward. cient length of caliber to utilize nearly all the expansive force of the powder.

The spherical form of this gun gives a great advantage by allowing the gun to be simply rotated on its trunnions, in order to be loaded without exposing the men by the presence of any open port-hole, and'the gun is so nearly balanced upon its trunnions F as to be worked with great ease, notwithstanding its weightiifty-one tons.

I intend this gun shall be protected from the enemys attacks by sufficiently thick armor to prevent its being broken or seriously deformed except on the small surface presented at the port-hole. As the gun is rolled or turned upon its trunnions a partial zone, a, is exposed to such missiles, some portion of such zone being exposed at one period and other portions of such .zone at another period, anda projectile is liable in striking thereon to indent the metal at one point and to push it out at another adjacent point. To diminish the evils due to this I prefer to sink or recess the surface of the gun slightly along the whole or a greater part of such exposed zone as is indicated in the figures.

I Some of the advantages pertaining to different features of my invention may be separately enumerated as follows:

First. By my arrangement of the steel B, which is hard and but slightly expansible by heat within the bronze A A", andlead G, which are more expansible by an equal degree of heat, and consequently are equally expanded with a less degree of heat, I cause the exterior metal,

A A to aid in resisting the mechanical force Second. By my arrangement of the exterior bronze, A interior bronze, A, connecting bronze A, and lead filling G, I secure a moderately higher temperature in the part A than in the part A", and obtain the mechanical strength due to both in a fuller degree under allconditions than by any means previously known tome. By virtue of this feature of my invention 1 am able to make guns of im- I suppose the gun has suffi- I mensely great diameter and to secure the whole or nearly the whole strength of the bronze under all conditions, and also to employ an immense weight to resist recoil, with the said weight very intimately incorporated into and balanced upon the gun.

Third. By the mechanical condensation of the outside of the outer shell, A and ot' the inside ofthe inner shell, A, and the forcing of the lead 0 with great pressure into the space .between these shells, I hold all the metal in a strained condition nearly equal to that which it will assume when the gun is fired. renders the parts less elastic and in echauieally supports the steel lining B with nearly the whole strength of the bronze before B is ex panded to any considerable extent. If the bronze were shrunk upcn the lining B with great force in a simple solid homogeneous mass,

1 the tendency to crush the lining would .be

which the particles near the inner surface of such solid and uniform mass would be not alone compressed in the direction of the radius of the gun, but would be distended or stretched in the direction of the circumference of the gun by reason of the mass being shrunk upon a lining of largerdiameter than the natural size of the hole in the bronze. This stretching of the metal near the inner surface ofvsuch a homogeneous mass is liable to be carried so far that radial cracks commence to form in that part, exactly as ordinary guns frequently commence to fail. This feature of my invention by making the whole mass less elastic in the manner shown avoids these evils and holds the lining B without undue compression, and yet forbids its expansion, even in the slightest degree, without meeting a support to which nearly the whole metal of A as well as A directly contributes.

Fourth. By my bed .of lead D, arranged as specified, I insure an equally perfect support of the part B by A at a point where it has been always difiicult by means heretofore heavy projectiles.

Filth. By the spherical form of the exterior of my outer shell, A', and consequently of the entire gun, I am able to keep the port always filled, or nearly so, while the gun is rotated and loaded. It is not essential that it be a perfect sphere to effect this purpose, as the slight recess a does ;not prevent this ad- This vantage from being realized; and an oblate spheroidal form might be substituted, or even a cylindrical or conical form. The axis of the latter forms lying in the line joining the trunnion might be employed with the same advantage so far as the constant protection of the men is concerned. It is, in fact, the wheel form of the gun, whether the wheel be spherical or not, which gives the specified advantage.

Sixth. By means of my shallow recess a, arranged as represented, I am able to rotate my gun without difficulty, even after it has been considerably roughened by the impact of heavy projectiles on the exposed surface. This recess is not so deep as to let missiles through to any considerable extent, and yet is sufficiently deep to allow the impact of shot &c., to cause the metal at adjacent points to protrude somewhat beyond the proper surfaceto wit, the base of the recesswithout meeting the edge of the port.

Having now fully described my invention, what I claim as new therein, and desire to secure by these Letters Patent, is as follows:

1. The within-described construction of guns of two or more metals having different rates of expansion by heat, a hard and slight- 1y expansible metal, B, being within the other or others, and so arranged that the exterior metal shall support and aid in resisting the mechanical force of the gases, and also allow the expansion of the several metals as they become heated by firing,substantially as above setforth.

2. The employment in such guns, of an exter-ior shell, A connected with an interior shell, A, by braces, A, with the intervals filled with material, 0, having less conducting power, the parts being arranged substantially in the manner and for the purpose above set forth.

3. In such guns, the mechanical condensation of the inner surface of the cylindrical shell A and the outer surface of the spherical shell A in combination with the filling of the space between them with a tightly-compressed material, C, substantially as and for the purpose above set forth.

4. In guns where alining is applied within a strengthening-shell, the employment of an intermediate bed of lead or the like plastic material D, in combination with the means of forcing in or releasing the plasticmaterial, substantially as above set forth.

5. The wheel form of the exterior of a gun adapted for use in combination with armor, substantially in the manner and for the purpose above set forth.

6. In such guns, the recess a, arranged substantially as and for the purpose above set forth.

NORMAN IVIARD.

\Vitnesses:

Ti-rotms D. S'rnTsoN, EMIL VOSSNACK. 

